/**
 *     __  ___
 *    /  |/  /___   _____ _____ ___   ____   ____ _ ___   _____
 *   / /|_/ // _ \ / ___// ___// _ \ / __ \ / __ `// _ \ / ___/
 *  / /  / //  __/(__  )(__  )/  __// / / // /_/ //  __// /
 * /_/  /_/ \___//____//____/ \___//_/ /_/ \__, / \___//_/
 *                                        /____/
 *
 * @description MessengerJS, a common cross-document communicate solution.
 * @author biqing kwok
 * @version 2.0
 * @license release under MIT license
 */
layui.define([], function (exports) {
    "use strict";
    var $=layui.$;
    var Messenger =  function(){

        // 消息前缀, 建议使用自己的项目名, 避免多项目之间的冲突
        // !注意 消息前缀应使用字符串类型
        var prefix = "[PROJECT_NAME]",
            supportPostMessage = 'postMessage' in window;

        // Target 类, 消息对象
        function Target(target, name, prefix) {
            var errMsg = '';
            if (arguments.length < 2) {
                errMsg = 'target error - target and name are both required';
            } else if (typeof target != 'object') {
                errMsg = 'target error - target itself must be window object';
            } else if (typeof name != 'string') {
                errMsg = 'target error - target name must be string type';
            }
            if (errMsg) {
                throw new Error(errMsg);
            }
            this.target = target;
            this.name = name;
            this.prefix = prefix;
        }

        // 往 target 发送消息, 出于安全考虑, 发送消息会带上前缀
        if (supportPostMessage) {
            // IE8+ 以及现代浏览器支持
            Target.prototype.send = function (msg) {
                this.target.postMessage(this.prefix + '|' + this.name + '__Messenger__' + msg, '*');
            };
        } else {
            // 兼容IE 6/7
            Target.prototype.send = function (msg) {
                var targetFunc = window.navigator[this.prefix + this.name];
                if (typeof targetFunc == 'function') {
                    targetFunc(this.prefix + msg, window);
                } else {
                    throw new Error("target callback function is not defined");
                }
            };
        }

        // 信使类
        // 创建Messenger实例时指定, 必须指定Messenger的名字, (可选)指定项目名, 以避免Mashup类应用中的冲突
        // !注意: 父子页面中projectName必须保持一致, 否则无法匹配
        function Messenger(messengerName, projectName) {
            this.targets = {};
            this.name = messengerName;
            this.listenFunc = [];
            this.prefix = projectName || prefix;
            this.initListen();
        }

        // 添加一个消息对象
        Messenger.prototype.addTarget = function (target, name) {
            var targetObj = new Target(target, name, this.prefix);
            this.targets[name] = targetObj;
        };

        // 初始化消息监听
        Messenger.prototype.initListen = function () {
            var self = this;
            var generalCallback = function (msg) {
                if (typeof msg == 'object' && msg.data) {
                    msg = msg.data;
                }

                var msgPairs = msg.split('__Messenger__');
                var msg = msgPairs[1];
                var pairs = msgPairs[0].split('|');
                var prefix = pairs[0];
                var name = pairs[1];

                for (var i = 0; i < self.listenFunc.length; i++) {
                    if (prefix + name === self.prefix + self.name) {
                        self.listenFunc[i](msg);
                    }
                }
            };

            if (supportPostMessage) {
                if ('addEventListener' in document) {
                    window.addEventListener('message', generalCallback, false);
                } else if ('attachEvent' in document) {
                    window.attachEvent('onmessage', generalCallback);
                }
            } else {
                // 兼容IE 6/7
                window.navigator[this.prefix + this.name] = generalCallback;
            }
        };

        // 监听消息
        Messenger.prototype.listen = function (callback) {
            var i = 0;
            var len = this.listenFunc.length;
            var cbIsExist = false;
            for (; i < len; i++) {
                if (this.listenFunc[i] == callback) {
                    cbIsExist = true;
                    break;
                }
            }
            if (!cbIsExist) {
                this.listenFunc.push(callback);
            }
        };
        // 注销监听
        Messenger.prototype.clear = function () {
            this.listenFunc = [];
        };
        // 广播消息
        Messenger.prototype.send = function (msg) {
            var iframes=top.window.document.getElementsByTagName("iframe");
            // 先清空原来的
            this.targets = {};
            for(var i = 0;i<iframes.length;i++){
                Messenger.addTarget(iframes[i].document,iframes[i].HTML()); 
            }
            var targets = this.targets,
                target;
            for (target in targets) {
                if (targets.hasOwnProperty(target)) {
                    targets[target].send(msg);
                }
            }
        };
        return Messenger;
    };
    exports("zlmessenger",Messenger);
});
